Objectives: 1. To determine the extent to which glycolysis in brains of fetal animals (rats) influences survival during anoxia. 2. To clarify the role of brain glycogen as a potential energy store in protecting fetuses during anoxia. 3. To investigate in perinatal animals regional differences in oxidative and energy metabolism which might affect anoxic vulnerability. Methods: 1. Measurements of glycolytic and tricarboxylic acid intermediates and high energy compounds in brains of fetal and postnatal rats following decapitation. From the measurements glycolytic flux, glucose consumption and cerebral metabolic rates will be estimated. 2. Measurements of components and enzymes of cerebral glycogen synthesis and catabolism under physiologic and pathophysiologic conditions in perinatal rats. 3. Measurements of glucolutic flux and cerebral metabolic rates in various areas of perinatal rat brain to determine regional development characteristics of cerebral oxidative metabolism. Significance: To gain insight into biochemical mechanisms underlying perinatal cerebral hypoxic resistance, which might lead to improved modes of therapy to prevent hypoxic-ischemic brain damage.